"Pertussis infex down after vax intro"

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"Pertussis infex down after vax intro"
Fri, 08-08-2003 - 1:22am

Pertussis Infections Down After Introduction of Acellular Pertussis Vaccines

By Will Boggs, MD

NEW YORK (Reuters Health) Jul 30 - The introduction of acellular pertussis vaccines in Germany has led to a decrease in the number and severity of Bordetella pertussis cases relative to B. parapertussis and other viral or bacterial infections, according to a report in the August issue of the Archives of Disease in Childhood.

After the general recommendation for pertussis vaccination was discontinued in Germany in 1975 over concerns regarding the safety of the whole cell pertussis vaccines, vaccination rates fell and pertussis became one of the most endemic infections among infants and children, the authors explain.

To examine the effect of the introduction in 1994 of acellular pertussis vaccines, Dr. Johannes Liese and associates from University Children's Hospital in Munich, Germany examined the incidence and clinical spectrum of B. pertussis and B. parapertussis in children between 3 and 8 years of age in German pediatric practices.

The incidence of B. pertussis fell from 21.7 to 4.8 per 1000 person-years after the introduction of acellular pertussis vaccines, the authors report, whereas the incidence of B. parapertussis increased slightly from 1.6 to 2.8 per 1000 person-years.

While 62% of the B. pertussis cases were fully vaccinated, the report indicates, 30% had never received any dose of pertussis vaccine.

Children who had received at least one dose of a pertussis vaccine showed a shorter total duration of any cough and a reduction in cough symptoms compared to children who had not been vaccinated, the researchers note.

Vaccinated children who were infected with B. parapertussis showed no significant difference from unvaccinated children in the duration of any cough, the investigators found, but vaccinated children showed a lower occurrence and duration of paroxysmal cough and post-tussive whooping.

"Pertussis in vaccinated children is usually mild, and may be difficult to distinguish from cough disease caused by B. parapertussis and other viral or bacterial infections," Dr. Liese told Reuters Health by e-mail. "It is important, however, to diagnose those cases, since they might transmit the infection to other children, who if unvaccinated are of risk for complications (e.g., infants in the first 6 months of life)."

He added, "B. parapertussis is another important possible cause of prolonged cough disease, probably not prevented by acellular pertussis vaccines."

Arch Dis Child 2003;88:684-687.